The Arc will connect to the TV’s HDMI ARC port and act as the center, front left, and front right channels. The One SLs will connect wirelessly to the Arc as surrounds. With this setup, the Amp is no longer needed.
I would consider selling the Amp and using the money to add a Sub to complete the 5.1.2 setup.
Amp won’t be needed.
Connect Arc to the TV.
Add SLs as surrounds.
You can use the Amp elsewhere if you add conventional speakers to it. A bedroom, office or kitchen might be nicer with Sonos sound.
Sonos offers a few speakers that work well with your Amp.
https://www.sonos.com/en-us/shop/architectural
Take a look at Crutchfield for some speaker shopping, try to find a set to listen to before buying if at all possible.
Bookshelfs, nice options in the $100-250 range: https://www.crutchfield.com/g_37900/Bookshelf-Speakers.html?&o=p
They also offer: In-ceiling speakers - In-wall speakers - Outdoor speakers but without the Sonos tweaks.
FYI, You may not get Dolby Atmos unless your TV has HDMI eARC. You didn’t mention it in your post. In any event the Arc will still deliver great sound for DD5.1 and DTS: 5.1 (if your TV will pass through the latter of the two formats mentioned).
Getting Atmos from TV sources (like the Netflix app) is possible without eARC. ARC will transport a DD+ stream with Atmos if the (apps on) the TV allow it.